<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	<style type="text/css">
		
		*{
			margin: 0;
			padding: 0;
		}
		.one{
			/*
			width: 200px;
			 如果变成半圆 将高度变为一半 
			height: 200px;
			border: 1px solid #000;
			box-sizing: border-box;
			margin: 100px auto;
			border-radius: 100px 100px 0 0 ;
			*/
		   
		   width: 200px;
		   height: 200px;
		   border: 1px solid #000;
		   box-sizing: border-box;
		   margin: 100px auto;
		   /*水平方向的   垂直方向 */
		   border-top-left-radius: 100px 100px;
		   
		border-top-right-radius: 100px 100px ;
		   
		}
		
		
		.two{
			width: 400px;
			height: 200px;
			border: 1px solid #000;
			box-sizing: border-box;
			margin: 300px auto;
			border-top-left-radius:200px 100px ;
			border-top-right-radius:200px 100px ;
				border-bottom-left-radius:200px 100px ;
			border-bottom-right-radius:200px 100px ;
		}
	</style>
	</head>
	
	<body>
		<div class="one"></div>
				<div class="two"></div>
	</body>
</html>